Copolymers of vinylidene cyanide with 2-mono-halogenated monoolefins



Patented Oct. 28, 1952 COPOLYMERS OF YINYLIDENE CYANIDE WITH Z-MONO-HALO GENATED MONO- OLEFIN S Vernon L. Folt, Akron, Ohio, assignor to The B. F.

Goodrich Company, New York, N. Y., a corporation of New York No Drawing. Application August 25, 1950,

Serial No. 181,588

10 Claims.

invention relates to the preparation of novel copolymers of vinylidene cyanide with certain halogenated monoolefins, particularly 2- chloropropene, which copolymers are extremely useful in the preparation of filaments and films. -In U. S. Patents 2,476,270 and 2,502,412 to Alan E.*Ardis, and 2,514,387 to Harry Gilbert, novel methods for the preparation of monomeric vinylidene cyanide are disclosed. In a copending application, Serial No. 11,336, filed February 26,

19 18, methods for preparation of useful homopoiymers of vinylidene cyanide are disclosed.

Monomeric vinylidene cyanide is a clear liquid iatroom temperature and a crystalline solid at f; 0. It melts in the range of 6.0 C. to 9.7 C., fdependingon purity, with purest samples melting fat 9'.0 C. to 937 C., and itboils at 40 C. at a re- :Yduced pressure of mm. of mercury. It is quite unstable because of its extreme sensitivity to water, undergoing on contact with water at room temperature an instantaneous homopolymeriza fition reaction to give a solid, water-insoluble resin. When it is allowed to stand at room tem.- :perature in admixture with butadiene-1,3, it reacts therewith to give solid 4,4-dicyanocyclohexene.

It has now been discovered that monomeric vinylidene cyanide of the above physical and chemical characteristics will copolymerize with halogenated monoolefins in the presence of a free --radical catalyst to give new and highly useful =copo1ymers. It has also been discovered that l -when the polymerization is carried out in such manner that the total monomer charge contains from 1 to 50 mole per cent of monomeric vin- 'ylidene cyanide, the copolymers obtained are even :further unique in that they are essentially 1: 1 alternating copolymers, that is, copolymers pos- 'sessing the structure:

a wherein each M1 is a vinylidene cyanide unit [iii] .1. "a

i essentially 50 mole per cent of vinyli d that is one unit of vinylidene cyanide enters the Jcop'olymer structure for each unit of the halogenated monoolefin. The composition of the copolymers may'be described by the following copolymerization equation of F. Lewis, C. Walling, W. Cummings, E. Briggs, and F. Mayo, Journal of the American Chemical Society 70, 1519 wherein (M1):concentration of unreacted monomer Mi (M2):concentration of unreacted monomerMz n ratio of the rate constants for the reaction of an M1 radical with M1 and M2 respectively rz ratio of the, rate constants for the reaction of an M2 radical with Mzand M1 respectively When the units alternate the values of rr-and r: are small and the product of n and T2 (the values of T1 and n being determined by solving the equation above for n and 1'2 respectively) is equivalent to 0. It has been found that the values of T1 and n as calculated for the vinylidene cyanide-2% halogenated monoolefin copolymer system are small and the product is substantially zero, indicating that an essentially 1:1 alternating copolymer is formed. 1

It is highly surprising that vinylidene cyanide will polymerize .so readily with Z-halogenated monoolefins, which are ordinarily very difficult to polymerize by themselves, since most polymerizable materials form useful copolymers only with other monomers which can be polymerized readily by themselves. The 2-halogenated monoolefins which. are polymerized with vinylidene cyanide in accordance with this invention possess the structure R-JJ=0H. wherein R is a lower alkyl radical such as methyl,- ethyl, propyl, or butyl, and Y is a halogen atom such as chlorine, fluorine, bromine, or iodine. Because of its low cost and the fact that it may be readily obtained in commercial quantities, 2-chloropropene is a preferred monomer for use in the polymerization with vinylidene cyanide. However, other monomers of the above general class, including 2-chlorobutene, 2-chloropent'ene, 2-chlorohexene, 2-chloroheptene, 2-bromobutene, 2-bromoheptene, Z-fluorohexene, 2-fiuorobutene, Z-iodopropene, 2-iodopentene, 2-iodoheptene,-ai1d the like may likewise be polymerized with vinylidene cyanide.

The polymerization itself may be carried out in several different ways. For example,"one pref ferred method consists simply in heating a mix ture of the monomers and polymerization catalyst, without the use of a solvent or other liquid medium for the monomers, to effect the polymerization. The polymerization occurs readily at temperatures of about 20 C. to 100 C., the copolymer forming generally as a white resinous powder of small particle size.

A second method, of polymerization consists in first dissolving the vinylidene cyanide and the 2-halogenated monoolefin in benzene or other liquid aromatic solvents such as toluene, methyl toluene, trichlorobenzene, or the like, preferably free from impurities which initiate the ionic polymerization of the monomer and in an amount such that the solvent comprises approximately 30 to 80% by weight of the totalsolutiom A poly Examples I to VIII A series of eight vinylidene cyanide-2-chloropropene copolymers is prepared by admixing 5 varying amounts of both monomers with 0.15% (based on the total weight of the two monomers) of o,o'-dichlorobenzoyl peroxide and maintaining the resulting mixtures at a temperature of 40 C. for from 105 to265 minutes. The copolymer obtainedat the end of this period is then analyzed to determine its composition. The vinylidene cyanide charging ratio, the time during which the polymerization is carried out, the per cent nitrogen in the copolymer and the mole per cent of vinylidene cyanide in the copolymer are recorded inthe following table:

Ex. I Ex. II Ex. III Ex. IV Ex. V Ex. VI Ex. VII Mole "percentvinylidene cyanide in eharge.- .w-.- 1. 963 4. 910 9.829 14. 158 24.644 49. 524 72. 641 89.835 Polymerization time (minutes) 165 105 105 105 105 105 265 265 Percent nitrogen in copolymer 17:78 181 20 18.39 18.43 17. 96 '19. 50 23. 64 27. 74 Mole percent vinylidene cyanide in 7 copolymer 49. 017' 50. 13 50. B8 50, 78 49. 46- 53. 2O 65. 42- i 76. 87

merization catalyst is included in this solution and the resulting mixture is maintained at the desired temperature whereupon polymerization occurs toiorm the desired copolymer. The 00- polymer thus formed may be separated from the polymerization medium simply by filtering, or if desired the solvent may be removed by evaporation. Also, the polymerization may be" effected at temperatures as low as 0. C. or lower orja's high as 100 C. or 'evenhigherrprovided a catalyst is utilized which will dissociate into free radicals at the. polymerization temperature.

It is to 'be understood, of. course, that regardless of the polymerization method utilized, the polymerization should be stopped before either of. the monomers is entirely :consumed;' in order that 'truecopolymer will be obtained. Otherwise, when either of the monomers is completely used up, the product will contain straight polymer obtained -by polymerization of the remaining monomer. Accordingly, it is often desirable to add, continuously or intermittently, fresh quant ties of one or both of the monomers,'and also of catalyst and solvent, if desired, to the polymerization mixture during the course of the polymerization, thus taking fullest advantage of the capacity of the equipment and in .efiect operating a continuous or semi-continuous process.

The catalyst which is used in the polymerization is preferably a peroxygen compound such as silver peroxide, the perborates, the percarbonates ,-benzoyil peroxide, caproyl peroxide, lauroyl peroxide, acetone peroxide, acetyl benzoyl peroxide, cumene hydroperoxide, 'o,o'-dichlorobenzoyl peroxide, o,o'-dibromobenzoyl peroxide, caprylyliperoxide, pelargonyl peroxide. tertiary .butyl hydroperoxide, tetralin peroxide, and the like. In general, from 0.0lto 2.0% by weight of the catalyst based :on the weight of the monomers isutilized-although smaller or larger amounts may be utilized if desired. Thejfollowing examples illustrate the prepara tion of copolymers of vinylidene'cyanide and 2-.- halogenated monoolefins in accordancewith this invention, but are not to be construed as a limitation upon the scope thereof, for there are,'of course, numerous possible variations and modifications. 'In-theexarnple s all parts are-by'weight.

When other Z-halogenated mono.olefins.select. ed from those disclosed hereinabove .are .siibsti tuted .for 2-chloropropene in the above examples, the copolymers obtained possess properties gen; erally equivalent to the vinylidene cyanidez c'hioropropene copolymer. Likewise, when the polymerization is carried out according to the other methods described hereinabove or utilizing other of thep'eroxygen catalysts disclosed, excel lent results areachieved. v

The copolymersj which are prepared according to this. invention are characterized by ahigh degree of alkaline .insensitivity and by. being soluble in dimethyl formamide. .The essentially 1,:1 alternating copolymers oi. this inventionare further characterized. by possessirigsoftening points of from about .140 to 150 c. -.-This1latter property renders the copolymers quite useful in the preparation of molded objects and they may also he melt spun or cast into excellent films. Moreover, as disclosed hereinabove, the copolymers arev useful in the preparation of solutions from which can be spun filaments of any desired size having high tensile strength, excellentr sistance to the action of alkalis and acids as well as-many other advantageous properties.

Although specific examples of the invention have beenherein described; it is not intended to limitthe invention solely thereto, but to include all or r the 'variations and modifications falling within the spirit and scope of the-appended claims.

I claim:

1; A copolymer of vinylidene cyanide and a" compound of the structure instantaneous homopolymerization reaction to give a solid, water-insoluble resin.

2. The copolymer of claim 1 wherein the compound of the structure halogen atom, said copolymer possessing essentially the structure wherein each M1 is a vinylidene cyanide unit of the structure HCN each M2 is a unit of said 2-halogenated monoolefin of the structure and a: is a number, the vinylidene cyanide units in said copolymer being derived from monomeric vinylidene cyanide which is a liquid at room temperature and a crystalline solid at 0 C. having a melting point when in purest form of substantially 9.0 C. to 917 C., and being characterized chemically by the ability to undergo on contact with water at room temperature an instantaneous homopolymerization reaction to give a solid, water-insoluble resin.

4. The copolymer of claim 3 wherein the 2- halogenated monoolefin is 2-chloropropene.

5. The method which comprises admixing monomeric vinylidene cyanide, said monomeric vinylidene cyanide being a liquid at room temperature and a crystalline solid at 0 C. having a melting point when in purest form of substantially 9.0 C. to 9.7 C., and being characterized chemically by the ability to undergo on contact with water at room temperature an instantaneous homopolymerization reaction to give a solid, water-insoluble resin, with a 2-halogenated monoolefin of the structure wherein R is a lower alkyl radical and Y is a halogen atom, and with a peroxygen catalyst, and maintaining the resulting mixture at a temperature of about 20 C. to 100 C. for a time sufiicient to effect copolymerization of the said vinylidene cyanide and 2-halogenated monoolefin and formation of a solid, resinous copolymer of vinylidene cyanide and the 2-halogenated monoolefin.

6. The method of claim 5 characterized in that the compound of the structure Y R=CH2 is 2-chloropropene.

7. The method of claim 6 further characterized in that the peroxygen catalyst is o,o-dichlorobenzoyl peroxide.

8. The method which comprises admixing monomeric vinylidene cyanide, said monomeric vinylidene cyanide being a liquid at room temperature and a crystalline solid at 0 C. having a melting point when in purest form of substantially C. to 917 C., and being characterized chemically by the ability to undergo on contact with water at room temperature an instantaneous homopolymerization reaction to give a solid, water-insoluble resin, with a 2-halogenated monolefin of the structure wherein R is a lower alkyl radical and Y is a halogen atom, in an amount such that the mixture contains from 1 to 50 mole per cent monomeric vinylidene cyanide, adding a peroxygen catalyst, and maintaining the resulting mixture at a temperature of about 20 C. to C. for a time sufiicient to efiect copolymerization of the said vinylidene cyanide and 2-ha1ogenated monoolefin and formation of a solid, resinous copolymer of the structure wherein each M1 is a vinylidene cyanide vunit of the structure each M2 is a unit of said Z-haIogenated monoolefin of the structure and a: is a number.

9. The method of claim 8 further characterized in that the compound of the structure Y R=OH1 is 2-chloropropene.

10. The method of claim 9 further characterized in that the peroxygen catalyst is o,o'-dichlorobenzoyl peroxide.

VERNON L. FOLT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,466,395 Dickey Apr. 5, 1949 

1. A COPOLYMER OF VINYLIDENE CYANIDE AND A COMPOUND OF THE STRUCTURE 